A proprietor of a restaurant or tavern has a vested interest in providing prompt service to his or her customers while controlling operating costs. Prompt service may include minimizing the time that a customer spends waiting for a beverage refill. Such time may include unnecessary delays of various kinds—the customer's delay in noticing that his or her beverage is nearly empty or the wait staff's delay in asking the customer if a refill is desired. Providing a larger wait staff in the restaurant or tavern may reduce some of the unnecessary delays, but it also may result in greater operating expenses.